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Thread: HW 90 Pump & Adapter !

  1. #1
    Join Date
    Nov 2005
    barton on humber

    HW 90 Pump & Adapter !

    Hi, I bought a HW90 a short while ago, It was making 9 Fpe,
    I was loaned a Theoben hose & pump by one of the forums " Gentlemen "

    He did mention that one of his Gas ram rifles he could only pump to 10 Fpe because of the effort required,
    Now the pump & the hose are not of the quality you would expect from
    Theoben ???? I never tried the Theoben pump.

    So I made this ( Sorry about the poor Pic )

    Its an adapter to fit the Stirrup pump, I started to pump it to 15 Bar, Tried still the same, A couple more Bar, Still the same, A little more, No change,
    I thought I would try 22 Bar ish, ( I say " ish " ) because the gauge on the pump is 0-250 Bar & difficult to add 1, or 2, more !
    And " Wow "

    You could feel the difference in cocking, But shooting it felt the same, Recoil & noise were the same ! ( It does have a moving Inertia weight to reduce recoil ) I read on one site its decribed as Semi-recoiless !
    The 80 doesn,t have one !

    By judicious tapping of the Schrader valve, I was able to release pressure & drop the output to 11.8 Fpe ( I just bet, Someone will come on & say thats too close, ) Maybe that will stop them .

    The stirrup pump required no effort at all, All connections were only finger tight, A very simple task,
    I was thinking I might make up a batch ( Gun to stirrup pump ) But I have to buy some parts to make them, What do you think ! Ged.
    Last edited by gedfinn 2; 09-09-2010 at 04:57 AM. Reason: spelling

  2. #2
    Join Date
    Nov 2005
    Hi Gedfinn,

    11.8 is too close! (insert gay smiley thing with tongue out)

    I have to agree that the HW pump is a Heath Robinson affair. I have found that you need to give it about ten good pumps to charge the pump and line before it starts to fill the cylinder. Without a gauge it is hit or miss to know the right amount (see one of my first posts about letting fly with a super sonic .17 pellet in the back garden!) I also found that tapping the release valve can dump the whole lot in one go too!

    Certainly the stirrup pump is the way forward and I'm suprised no-one has made an adaptor for the HW90 et al before. I'm sure you'll have a few interested parties for it. Good work fella.

    Cheers Boondock

  3. #3
    Join Date
    May 2010
    It looks to be a good idea.

    My neigbour is a mountain bike fanatic, and he has a stirrup pump for doing his bike tyres.

    Its a good quality affair, and I borrow it to do my car and motorcycle tyres, and its very very easy.

    As the guage on it has a more suitable range (up to about 50psi I think), maybe it would be ideal for this application...???

    opps just realise i read BAR for PSI....scrap the above!!!!!!!
    Last edited by Vonnegut; 09-09-2010 at 08:15 AM. Reason: I am a fool

  4. #4
    vasbyt.skollie is offline The impossible I can do, Miracles take time..
    Join Date
    Jan 2009

    Smile Adaptor

    I have been using a similar setup with my Logan stirrup pump for a few years now. Once a year I strip, clean, check/replace the O rings and tophat, relube and then pump it up to give me +- 11.4fpe with webley mozzies. I agree 11.8 is a little high if your using a heavy pellet as with a lighter pellet you'll be over the top. Better be SAFE than sorry
    Cheers and safe shooting
    Last edited by vasbyt.skollie; 12-09-2010 at 04:12 PM.
    Gas operative extraordinaire

  5. #5
    Join Date
    Mar 2009


    [QUOTE=gedfinn 2;4522107]Hi, I bought a HW90 a short while ago, It was making 9 Fpe,
    I was loaned a Theoben hose & pump by one of the forums " Gentlemen "

    So I made this ( Sorry about the poor Pic )

    Sorry about the late reply, only just found the info. What size is the adaptor to fit the HW90 rear end? Just bought a couple of adaptors which were supposed to fit, they were sent as 1/8" to 1/8" BSP male/male, but I reckon they are more like 3/8". It fits the stirrup pump hose no probs but far too big for the female schrader housing. Thanks in advance. Gordon

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